Embodiments of the present invention relate broadly to seating units designed to support a user's body in an essentially seated disposition. Commonly, seating units include a backrest and/or a seat that are constructed with a hardness or firmness, which is established by stressing a fabric and fastening the stressed fabric to a frame. By way of example, a mesh-type fabric may be manually stretched and stapled to a frame to provide structure for a seat or a backrest of an automotive-style seating unit in order to support an occupant within a specific hardness or firmness. This hardness or firmness is fixed because it is based on permanent characteristics (e.g., flexure, thickness, material traits) of the fabric and the amount of stress that is applied to the fabric before attachment. Because manually stretching a fabric can impart only a limited amount of stress to fabric, the hardness or firmness of the assembled seat or backrest may not be high enough to provide proper support the occupant. Accordingly, the occupant of the seating unit (e.g., operators of the vehicle) with an individualized preference of hardness or firmness will likely experience discomfort when sitting in the seating unit for a period of time.
Consequently, integrating a frame pre-forming operation into an inline assembly of seats and/or backrests to allow for consistent, increased firmness of portion(s) of a seating unit would enhance the user's experience (e.g., level of comfort or support) when occupying the seating unit. Accordingly, embodiments of the present invention pertain to a novel method that involves deforming a frame prior to loading a fabric within the frame; thus, increasing the amount of tension (longitudinal and/or lateral) carried by the fabric upon being secured to the frame. The longitudinal and/or lateral tension may be adjusted by the amount of frame deformation to achieve a desirable level of firmness within the seating unit. This level of firmness may be based on an indication provided by a customer or other design specifications.